The Eastern Empire was vastly different from the West. The East contained the largest population centers and the wealthiest cities. The moving of the capital to Constantinople by Constantine added the element of prestige and signified the importance of the East. Dominated by ancient civilizations that predated Rome, the East was far more eclectic and open to competing philosophies and religious ideals. The Christian population in the East, for example, was substantially higher than in the West.
The West was more prone to barbarian incursions as Germanic tribes invaded Gaul and eventually Italy during the 5th Century. Western legions were often composed of barbarian recruits, men that had no loyalty to Rome nor shared common interests related to imperial goals. As civil government crumbled, the Catholic Church emerged as both civil and spiritual leader under the auspices of local bishops whose seats coincided with the Roman civitates.